Valve insufficiency and regurgitation is a potentially grave health issue that can lead to cardiac dysfunction. Mitral valve insufficiency may comprise a valve that does not completely shut and affect the seal between the left ventricle and the left atrium. Historically, such a condition necessitated surgical intervention.
Surgical repair of mitral valve insufficiency historically involved the use of a sternotomy or a similar invasive procedure. After performing a sternotomy, the patient's heart would be stopped while the surgeon transected the chambers of the heart to gain access to the mitral valve. Upon attaining access to the mitral valve, the surgeon could then repair the valve by an annuloplasty, or suturing the valve. These procedures are complex, time consuming, and involve many risks attendant with open cardiac surgery. Complications may occur, and recovery time may be significant.
Catheter based valve replacement has been proposed as a way to avoid open-heart surgery. Such procedures involve excision of the native valve and replacement of the native valve with a prosthetic valve, or installation of a prosthetic valve over the native valve, or a device to repair the damaged valve. Previous proposed treatments involve the use of clips to bind the posterior and anterior leaflets of the mitral valve. To avoid cardiopulmonary bypass, the catheter based valve replacement is performed on a beating heart. Following excision of the native valve, no valve is present to preserve the pumping action of the heart while the permanent prosthetic valve is being implanted.
An additional consideration in both open-heart and catheter based valve replacement is the healing process after the prosthetic valve is implanted. After the surgical valve replacement procedure, scar tissue must form around the sewing cuff to secure the prosthetic valve in position. In current practice, multiple knotted sutures anchor the prosthetic valve in place until in-growth of scar tissue into the sewing cuff takes over the load bearing function. However, the placement of knotted sutures through a catheter can be very difficult and time consuming.
Artificial heart valves for temporary use are known in the art, but present certain problems. Some designs are complex, requiring alternating the inflation and deflation of balloons to alternately block and permit flow. Such designs require complex sensing and control systems. Other designs fail to provide access for tools that must reach the valve site for removal of the native valve and placement of the prosthetic valve. Yet other designs require elaborate supporting frames to hold the valve portion.
Alternative procedures to effect cardiac valve regurgitation involve the implantation of a device into the coronary sinus near the mitral valve. Some of these devices attempt to correct mitral valve regurgitation by placing a compressive force on the coronary sinus that then compresses at least a portion of the mitral valve annulus adjacent the coronary sinus. The resultant reduction in annulus radius brings the valve leaflets closer together to decrease the valve regurgitation. Still other devices that are implanted in the coronary sinus attempt to decrease valve regurgitation by straightening the radius of the coronary sinus. Straightening the coronary sinus results in a corresponding straightening of a portion of the mitral valve annulus adjacent the straightened coronary sinus. The intended result is to draw the valve leaflets closer together to decrease the valve regurgitation. One drawback to these implanted devices is that the size and shape of these devices often impede the flow of blood through the coronary sinus.
It would be desirable, therefore, to provide an apparatus and method for reducing cardiac valve regurgitation that overcomes these and other disadvantages.